The present invention relates to a composition based on a dicyclopentenyloxyalkyl ester of (meth)acrylic acid, the said composition being intended to be used in the building sector, as binder in the preparation of synthetic resin concretes or mortars, or as bonding primer, or alternatively as finishing coat, in which case the composition can contain one or more pigments in order to obtain the desired final colour.
The development of floorings based on methyl methacrylate resin concretes or mortars has made it possible to be able to carry out construction operations under temperature conditions close to 0.degree. C., conditions under which epoxy- or polyurethane-based systems are inoperative. Moreover, the low viscosity of this monomer introduces the advantage of thoroughly filling the spaces and cracks, thus improving the mechanical behaviour. However, the major disadvantages of the use of methyl methacrylate are its odor, its low ignition point and its high shrinkage.
With the aim of reducing these disadvantages, the use of a particular methacrylic monomer, namely dicyclopentenyloxyethyl methacrylate (DCPOEMA), has been proposed in Patents U.S. Pat. No. 4,299,761, EP-A-47,120, U.S. Pat. No. 4,400,413 and U.S. Pat. No. 4,460,625. This monomer, which has a high boiling point and which carries two double bonds of different natures and reactivities, in fact possesses a very slight odor and results in shrinkage which is markedly less than that of methyl methacrylate.
The use having a monomers of high boiling point and a high molar mass poses, however, problems of limitation of the rate of surface polymerization due to inhibition by atmospheric oxygen which is reflected by the persistence of a stickiness for a period of time ranging up to more than 24 hours. These problems are particularly evident when DCPOEMA and analogous monomers are used.
In accordance with the abovementioned patents, this problem can be solved by covering the surface with an immiscible liquid which forms a barrier to oxygen and which can contain a polymerization initiator. This solution nevertheless brings with it the disadvantage of causing the appearance of the fillers at the surface and of reducing the chemical resistance of the material.
It is also known that the use of salts or complexes of transition metals, such as cobalt, manganese and zirconium, commonly called drying agents, makes it possible to reduce the curing time of the surface without, however, falling below 8 hours. In order to increase the drying rate and to decrease the water gain, it is also possible to incorporate unsaturated fatty acids as described in European Patent Application EP-A-157,596. However, this improvement in the drying time still does not make it possible to obtain a time during which stickiness is displayed which is less than 6-8 hours. In order to inhibit the effect of oxygen, reducing agents, such as aldehydes and imines, can be added at the time of polymerization, as described in European Patent Application EP-A-169,702, with, however, the disadvantages of a possible premature oxidation of the aldehyde and of the necessity of the presence of water in order to open the imine functional group (blocked aldehyde functional group).
The development of synthetic resin concretes based on dicyclopentenyloxyethyl methacrylate and analogous compounds thus requires new solutions in order to solve the technical problems related to the low rate of drying of the coating.
Moreover, this market also demands materials exhibiting improved thermal resistance and good resistance to chemical agents, such as acids, bases and solvents.